More dynamic strucuture of supercoiled DNA revealed in 3D-imaging

Images of the three-dimensional structure of supercoiled DNA were revealed in a study published this week in the journal Nature Communications, showing the shape is much more dynamic than the double helix developed by scientists Watson and Crick in 1978.

The study showed with unprecedented detail the three-dimensional structure which according to research leader Dr. Sarah Harris from the University of Leeds, imaging these samples of “supercoiled” DNA can help scientists develop better medicines such as new antibiotics or more effective cancer chemotherapies.

Researchers at the Baylor College of Medicine and the University of Leeds have imaged, in unprecedented detail, the three-dimensional structure of supercoiled DNA, revealing that its shape is much more dynamic than the well-known linear double-helix. Credit: Bio Quick News

“Our study looks at DNA on a somewhat grander scale, several hundreds of base pairs and even this relatively modest increase in size reveals a whole new richness in the behavior of the DNA molecule,” said Harris as reported by EurekAlert.

A powerful microscopy technique was used by researchers at the Baylor College of Medicine to achieve the imaging which were later examined using supercomputer simulations run at the University of Leeds. Various DNA shapes including figure-8-s were identified against the well-known in popular culture double helix of the DNA.

“When Watson and Crick described the DNA double helix, they were looking at a tiny part of a real genome, only about one turn of the double helix,” said Sarah Harris in a news release.

Researchers used an enzyme that manipulates the twist of DNA to make sure that twisted DNA acted the same way as the full-length DNA strands within our cells. They concluded that the DNA in the circles must look and act like the much longer DNA that the enzyme encounters in human cells.

These simulations showed the dynamic nature of the DNA, referring to it not as rigid and static as commonly believed, but more of a structure which constantly wiggles and morphs into different shapes.